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Enable microsecond timing #245

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Enable microsecond timing #245

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8 changes: 4 additions & 4 deletions FprimeZephyrReference/Components/Drv/RtcManager/RtcManager.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -28,10 +28,10 @@ void RtcManager ::configure(const struct device* dev) {
// ----------------------------------------------------------------------

void RtcManager ::timeGetPort_handler(FwIndexType portNum, Fw::Time& time) {
// Get system uptime
int64_t t = k_uptime_get();
U32 seconds_since_boot = static_cast<U32>(t / 1000);
U32 useconds_since_boot = static_cast<U32>((t % 1000) * 1000);
// Get system uptime in useconds
int64_t t = k_uptime_ticks();
U32 seconds_since_boot = static_cast<U32>(t / 1000000);
U32 useconds_since_boot = static_cast<U32>(t % 1000000);

// Check device readiness
if (!device_is_ready(this->m_dev)) {
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4 changes: 4 additions & 0 deletions prj.conf
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Expand Up @@ -10,6 +10,10 @@ CONFIG_MAIN_STACK_SIZE=8192
CONFIG_POSIX_API=y
CONFIG_REBOOT=y

#### System Clock Configuration ####
# Run system clock at 1 MHz for microsecond precision timing
CONFIG_SYS_CLOCK_TICKS_PER_SEC=1000000

@LeStarch LeStarch Dec 31, 2025

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This change will have a massive effect on the system. It will change interrupt timings, thread switching timings, and any other timings defined by the system. It will also increase overhead of kernel operations (context switching, etc) because these will happen more often.

Ticks represent the minimum time quantum that the kernel can detect and act on. We currently use 10000. This increases that value by 100x.

@nateinaction nateinaction Dec 31, 2025

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Ah, thank you for this clarification. I thought the objection was around changing the Zephyr call from k_uptime_get() to k_uptime_ticks(). Agreed this is worth looking into.


#### Native USB ####
#CONFIG_USB_DEVICE_STACK=y
#CONFIG_USB_CDC_ACM=y
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